Mobility and data rates for communications standards

workablejeansMobile - Wireless

Nov 21, 2013 (3 years and 10 months ago)

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Introduction


Roughly

speaking

there

are

two

types

of

wireless

networks
:


Local

Area

Networks

(LAN)


Bluetooth,

802
.
11

Family,

HiperLAN

Family,

HomeRF
...


Wide

Area

Networks

(WAN)


GSM,

3
G,

4
G,

Iridium
...

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Mobility and data rates for communications standards

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Two

main

standards

families

for

Wireless

Lan
:


IEEE

802
.
11

(
802
.
11
b,

802
.
11
a,

802
.
11
g
...
)


ETSI

HiperLAN

(HiperLAN

Type

1
,

Type

2
,

HiperAccess,

HiperLink
...
)


HiperLAN

Family

Hiperlan1

Hiperlan2

HiperAccess

HiperLink

Description

Wireless
Ethernet

Wireless ATM

Wireless Local
Loop

Wireless Point
-
to
-
Point

Freq. Range

5GHz

5GHz


5GHz


17GHz

PHY Bit Rate

23.5Mbps

6~54Mbps

~25Mbps

(data rate)

~155Mbps

(data rate)

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Motivation

of

HiperLAN




Massive

Growth

in

wireless

and

mobile

communications



Emergence

of

multimedia

applications



Demands

for

high
-
speed

Internet

access



Deregulation

of

the

telecommunications

industry

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The

History,

Present

and

Future



HiperLAN

Type

1


Developed

by

ETSI

during

1991

to

1996


Goal
:

to

achieve

higher

data

rate

than

IEEE

802
.
11

data

rates
:

1
~
2

Mbps,

and

to

be

used

in

ad

hoc

networking

of

portable

devices


Support

asynchronous

data

transfer,

carrier
-
sense

multiple

access

multiple

access

with

collision

avoidance

(CSMA/CA),

no

QoS

guaranteed
.


Products


Proxim's

High

Speed

RangeLAN
5

product

family

(
24
Mbps
;

5
GHz
;

QoS

guaranteed)


RadioLAN’s

products

for

indoor

wireless

communication

(
10
Mbps
;

5
GHz
;

Peer
-
to
-
Peer

Topology)

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HiperLAN

Type

2


Next

generation

of

HiperLAN

family
:

Proposed

by

ETSI

BRAN

(Broadband

Radio

Access

Networks)

in

1999
,

and

is

still

under

development
.



Goal
:

Providing

high
-
speed

(raw

bit

rate

~
54
Mbps)

communications

access

to

different

broadband

core

networks

and

moving

terminals


Features
:

connection
-
oriented,

QoS

guaranteed,

security

mechanism,

highly

flexibility


Product
:

Prototypes

are

available

now,

and

commercial

products

are

expected

at

the

end

of

2001

(Ericsson)
.


HiperAccess

and

HiperLink


In

parallel

to

developing

the

HIPERLAN

Type

2

standards,

ETSI

BRAN

has

started

work

on

standards

complementary

to

HIPERLAN

Type

2

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Typical

application

scenarios


HiperLAN
:

A

complement

to

present
-
day

wireless

access

systems,

giving

high

data

rates

to

end
-
users

in

hot
-
spot

areas
.


Typical

app
.

Environment
:

Offices,

homes,

exhibition

halls,

airports,

train

stations,

etc
.


Different

with

Bluetooth,

which

is

mainly

used

for

linking

individual

communication

devices

within

the

personal

area

network

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II. Hiperlan2 System Overview

Features


5 GHz technology, up to 54 Mbit/s


Generic architecture supporting:

Ethernet, IEEE 1394, ATM, 3G etc.


Connection
-
oriented with QoS per conn.


Security
-

authentication & encryption


Plug
-
and
-
play radio network using DFS


Optimal throughput scheme

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MAC

CAC

PHY

HiperLAN Type 1 Reference Model

PHY

MAC

EC

ACF

DCC

RLC

DLC

CL

HiperLAN Type 2 Reference Model

Control Plane

User Plane

MAC
:

Medium

Access

Sub

layer


EC
:

Error

Control

CAC
:

Channel

Access

Control

Sub

layer

RLC
:

Radio

Link

Control

PHY
:

Physical

Layer



RRC
:

Radio

Resource

Control

DLC
:

Data

Link

Control

Layer


ACF
:

Association

Control

Function

CL
:

Convergence

Layer



DCC
:

DLC

Connection

Control

Architecture

RRC

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Physical Layer



Data units on physical layer: Burst of variable
length, consist of a preamble and a data field


Reference configuration

1: information bits

2: scrambled bits

3: encoded bits

4: interleaved bits

5: sub
-
carrier symbols

6: complex baseband OFDM symbols

7: PHY bursts

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Spectrum

plays

a

crucial

role

in

the

deployment

of

WLAN


Currently,

most

WLAN

products

operate

in

the

unlicensed

2
.
4
GHz

band,

which

has

several

limitations
:

80
MHz

bandwidth
;

spread

spectrum

technology
;

interference


Spectrum

allocation

for

Hiperlan
2

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Modulation

scheme
:

Orthogonal

frequency
-
division

multiplexing

(OFDM)


Robustness

on

highly

dispersive

channels

of

multipath

fading

and

intersymbol

interference


Spectrally

efficient


Admits

great

flexibility

for

different

modulation

alternatives


Facilitated

by

the

efficiency

of

FFT

and

IFFT

algorithms

and

DSP

chips


Hiperlan
2
:

19

channels

(
20
MHz

apart)
.

Each

channel

divided

into

52

subcarriers

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Encoding
:

Involves

the

serial

sequencing

of

data,

as

well

as

FEC



Key

feature
:

Flexible

transmission

modes


With

different

coding

rates

and

modulation

schemes


Modes

are

selected

by

link

adaptation


BPSK,

QPSK

as

well

as

16
QAM

(
64
QAM)

supported


Mode

Modulation

Code rate

Physical layer
bit rate
(Mbps)

1

BPSK

½

6

2

BPSK

¾

9

3

QPSK

½

12

4

QPSK

¾

18

5

16
QAM

9/16

27

6

16
QAM

¾

36

7(
optional)

64
QAM

¾

54

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Data Link Control Layer

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Three

main

control

functions


Association

control

function

(ACF)
:

authentication,

key

management,

association,

disassociation,

encryption


Radio

resource

control

function

(RRC)
:

handover,

dynamic

frequency

selection,

mobile

terminal

alive/absent,

power

saving,

power

control


DLC

user

connection

control

function

(DCC)
:

setup

and

release

of

user

connections,

multicast

and

broadcast

Connection
-
oriented


After

completing

association,

a

mobile

terminal

may

request

one

or

several

DLC

connections,

with

one

unique

DLC

address

corresponding

to

each

DLC

connection,

thus

providing

different

QoS

for

each

connection

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DLC: MAC Sub layer


Basic frame structure (one
-
sector antenna)


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BCH

(broadcast

channel)
:

enables

control

of

radio

resources


FCH

(frequency

channel)
:

exact

description

of

the

allocation

of

resources

within

the

current

MAC

frame


ACH

(access

feedback

channel)
:

conveys

information

on

previous

attempts

at

random

access


Multibeam

antennas

(sectors)

up

to

8

beams

supported


A

connection
-
oriented

approach,

QoS

guaranteed

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HiperLAN

implements

QoS

through

time

slots


QoS

parameters
:

bandwidth,

bit

error

rate,

latency,

and

jitter


The

original

request

by

a

MT

to

send

data

uses

specific

time

slots

that

are

allocated

for

random

access
.


AP

grants

access

by

allocating

specific

time

slots

for

a

specific

duration

in

transport

channels
.

The

MT

then

sends

data

without

interruption

from

other

MT

operating

on

that

frequency
.


A

control

channel

provides

feedback

to

the

sender
.


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DLC
:

Error

Control


Acknowledged

mode
:

selective
-
repeat

ARQ


Repetition

mode
:

typically

used

for

broadcast


Unacknowledged

mode
:

unreliable,

low

latency

DLC
:

other

features


Radio

network

functions
:

Dynamic

frequency

selection
;

handover
;

link

adaptation
;

Multibeam

antennas
;

power

control


QoS

support
:

Appropriate

error

control

mode

selected
;

Scheduling

performed

at

MAC

level
;

link

adaptation
;

internal

functions

(admission,

congestion

control,

and

dropping

mechanisms)

for

avoiding

overload

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IV. Conclusion


Will

HiperLAN

standards

replace

802
.
11
?


There

will

be

a

fight

between

connection

and

connectionless

camps

Hiperlan
2
/
802
.
11
a


Current

products

under

development

and

becoming

available

only

offer

25
Mbps


Hiperlink

155
Mbps

data

rates

still

some

way

off


Wireless
:

Useful

as

an

adjunct

to

the

wired

world

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The End






…… Thank You ……

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